The Twin Peaks Tunnel, about 2.3 miles long, runs between the Castro and (appropriately named) West Portal neighborhoods of San Francisco. Originally built for streetcars, it was later transformed for light-rail use, becoming part of the region’s Muni Metro system. Although longer tunnels were built after this one, it’s still one of the world’s longest streetcar/light rail tunnels.
At the time, the western part of the San Francisco peninsula was just being developed, and the streetcar line was envisioned as a way to link those neighborhoods with downtown.
Three years ago, the Niles Silent Film Museum uncovered a 1916 silent film showing construction on the tunnel (originally commissioned by a real-estate company, it was probably intended to generate interest among potential residents). Restored by the National Film Preservation Foundation, the film shows the amount of manpower involved in such an endeavor. Steam shovels dig out the West Portal entrance near the beginning of the film. Mule teams haul dirt, and construction workers do many dirty jobs by hand.
The 19-minute movie also offers a glimpse of what San Francisco looked like a decade after much of the city was ravaged by earthquake and fire in 1906. The film shows an “auto parade” celebrating the opening of one tunnel section, and we see neighborhoods going up in the then-heavily forested Westwood Park area.
The Forest Hill Station (originally called the Laguna Honda Station) on the tunnel’s west end—the oldest subway station west of the Mississippi—is still in use as a Muni Metro light rail station and remains the deepest Muni rail station. The Eureka Valley Station on Market Street, at the tunnel’s east end, has only been used for detours and emergencies since the Castro Street Station replaced it in 1972.